Sandwich semigroups in locally small categories I: foundations

• Main Authors: Igor Dolinka, Ivana Đurđev, James East, Preeyanuch Honyam, Kritsada Sangkhanan, Jintana Sanwong, Worachead Sommanee
• Format: Journal
• Published: 2018
• Subjects: Mathematics
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85052379192&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/58795
• Institution: Chiang Mai University

© 2018, Springer Nature Switzerland AG. Fix (not necessarily distinct) objects i and j of a locally small category S, and write Sijfor the set of all morphisms i→ j. Fix a morphism a∈ Sji, and define an operation ⋆aon Sijby x⋆ay= xay for all x, y∈ Sij. Then (Sij, ⋆a) is a semigroup, known as a sandw...